“A lot of Bert’s antitrust opinions are annoying,” said R. Hewitt Pate, the general counsel of Chevron and a former senior antitrust official in the Bush administration. “You disagree with him on the substance but you enjoy hanging out with him, and there are not enough people in Washington like that.”

“At its root, antitrust is about human dignity and making sure consumers have a range of choices,” Mr. Foer said.